Vitamin D for Cold & Flu
Evidence-Based Natural Remedy Guide
Effectiveness
Type
supplement
Sources
1 cited
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How Vitamin D Helps with Cold & Flu
Vitamin D activates antimicrobial peptides and strengthens innate immune defense against respiratory viruses. Deficiency dramatically increases susceptibility to colds and flu.
🔬 What the Research Says
A 2017 meta-analysis in the BMJ of 25 trials (11,321 participants) found vitamin D supplementation reduced the risk of acute respiratory infections by 12% overall, and by 70% in those who were severely deficient.
📋 How to Use
Take vitamin D3 supplement daily with food containing fat. During cold/flu season, ensure adequate levels (40-60 ng/mL is optimal).
💊 Recommended Dosage
2000-4000 IU vitamin D3 daily for prevention. Higher doses may be needed if deficient.
⚠️ Side Effects & Cautions
Safe at recommended doses. Excessive intake over 10,000 IU daily may cause toxicity.
🛒 Where to Buy Vitamin D
NatureWise Vitamin D3 5000 IU
★★★★★ 4.8 · $10-15
Other Natural Remedies for Cold & Flu
Other Conditions Vitamin D Helps
📚 Sources
Last reviewed: February 2026 · Medical disclaimer applies
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